My guitar teacher has great chops, but he never uses them in his band. He is the composer fo the music, and he never gives himself solos (the music wouldn't really work with them)! He always pushes for me to improve my technique, but he never suggests that that is the be all and end all of playing. A couple of times when he gives me improv work to do he has just looked up, laughed, and said "that's ****!". Generally when he says that I already knew that I wasn't playing too well, so it's not as if he cuts me down when i feel like I'm doing really well.
Also, because he doesn't improvise very often, he sometimes is impressed by what I can do, and will then talk to me about what I just did, which is nice.